Communications system

ABSTRACT

A home base station registration request message includes data identifying whether or not the home base station comprises an open access mode or a closed access mode home base station.

The application is a Divisional Application of U.S. patent applicationSer. No. 13/854,785, filed on Apr. 1, 2013, which is a Divisionalapplication of U.S. patent application Ser. No. 12/998,472, filed onApr. 25, 2011, now U.S. Pat. No. 8,417,241, which is a National Stage ofInternational Application No. PCT/JP2009/069020, filed on Nov. 2, 2009,which is based on and claims priority from United Kingdom PatentApplication No. 0820182.4, filed on Nov. 4, 2008, the entire contents ofwhich is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to mobile telecommunication networks,particularly but not exclusively networks operating according to the3GPP standards or equivalents or derivatives thereof. The invention hasparticular although not exclusive relevance to the interface between ahome base station and a home base station gateway device.

BACKGROUND ART

Under the 3GPP standards, a NodeB (or an eNB in LTE) is the base stationvia which mobile devices connect to the core network. Recently the 3GPPstandards body has adopted an official architecture and started work ona new standard for home base stations (HNB). Where the home base stationis operating in accordance with the LTE standard, the HNB is sometimesreferred to as a HeNB. However, for simplicity, we will just use theterm HNB in the following description. The HNB will provide radiocoverage (3G/4G) within the home and will connect to the mobile networkvia a suitable public network (for example via an ADSL link to theInternet) and an HNB gateway (HNB-GW). As part of this standard settingprocess, the registration procedure between the HNB and the HNB-GW hasbeen agreed.

It has also been agreed that an access control mechanism is mandatory atthe HNB-GW whereas it is optionally provided for pre-release 8 UserEquipment (UE) at the HNB. Further, with the various evolving scenariosof HNB deployments, it is recognised that the HNB could operate withdifferent access control mechanisms, namely “Open”, “Closed” and“Hybrid”. As will be appreciated by those skilled in the art, if the HNBis open, then the mandatory access control at the HNB-GW is not requiredfor pre-release 8 UEs. If the HNB is hybrid, then the mandatory accesscontrol at the HNB-GW may not required for pre-release 8 UEs.

Although for efficiency of understanding for those of skill in the art,the invention will be described in detail in the context of a 3G system,the principles of the invention can be applied to other systems in whichmobile devices or User Equipment (UE) communicate with one of severalbase stations with the corresponding elements of the system changed asrequired.

DISCLOSURE OF INVENTION

Embodiments of the present invention aim to address one or more of theabove problems by making the HNB provide capability information to theHNB-GW.

According to one aspect, the present invention provides a methodperformed by a gateway device, the method comprising: receiving arequest to register a mobile communications device from a home basestation; determining if the home base station is an open access mode ora closed access mode home base station; performing access control forsaid mobile communications device if said determining step determinesthat the home base station is a closed mode home base station andregistering the mobile telephone with the gateway device if accesscontrol succeeds; registering the mobile telephone with the gatewaydevice, without performing access control, if said determining stepdetermines that the home base station is an open mode home base station;and sending a registration accept message to the home base station ifregistration of the mobile communication device is accepted.

In one embodiment, the gateway determines if the home base station is anopen or a closed access mode home base station based on informationreceived from the home base station, for example in a registrationrequest. The information may be defined by the presence or absence of anoptional element within the home base station registration request. Forexample, by the presence or absence of an Access Control List within thehome base station registration request, such that if the Access ControlList is present, then the gateway device determines that the home basestation is a closed access home base station and if the Access ControlList is absent, then the gateway device determines that the home basestation is an open access home base station.

Alternatively the information may be defined by the contents of amandatory element within the home base station registration request. Forexample, by the presence or absence of entries within said mandatoryelement. In one embodiment, the data is defined by the presence orabsence of entries within a mandatory Access Control List within thehome base station registration request, such that if the Access ControlList includes one or more entries, then the gateway device determinesthat the home base station is a closed access home base station and ifthe Access Control List is empty, then the gateway device determinesthat the home base station is an open access home base station.

The access mode of the home base station may be open, closed or hybridand the gateway may treat hybrid access mode home base stations as openaccess mode home base stations or as closed access mode home basestations or as both open and closed access mode home base stations. Inone embodiment, the mandatory element defines if the home base stationis an open access home base station, a closed access home base stationor a hybrid access home base station.

If the home base station is a hybrid access home base station, themethod may comprise performing access control for the mobilecommunications device and if it succeeds registering the mobiletelephone with the gateway device and generating data identifying thatthe mobile communications device is part of a closed subscriber groupassociated with the home base station; and if access control does notsucceed registering the mobile telephone with the gateway device andgenerating data identifying that the mobile communications device is notpart of a closed subscriber group associated with the home base station.

In another embodiment, the gateway determines if the home base stationis an open or a closed access mode home base station based on datastored within a central database, such as an Operations and Managementdatabase.

The present invention also provides a method performed by a home basestation, the method comprising: sending the gateway device dataidentifying whether or not the home base station is an open access modeor a closed access mode home base station; receiving a request from amobile communications device; transmitting a registration request forthe mobile communications device to the gateway device; and receiving aregistration accept message from the gateway device if registration ofthe mobile communication device is accepted.

The home base station may include the data within a home base stationregistration request message transmitted by the home base station.

In one embodiment, the data is defined by the presence or absence of anoptional element within the home base station registration request. Forexample, the data may be defined by the presence or absence of an AccessControl List within the home base station registration request, suchthat if the home base station is a closed access home base station thenthe home access base station includes the Access Control List in thehome base station registration request and if the home base station isan open access home base station then the home access base station doesnot include the Access Control List in the home base stationregistration request.

In another embodiment, the data may be defined by the contents of amandatory element within the home base station registration request. Forexample, the data may be defined by the presence or absence of entrieswithin said mandatory element. For example, the data may be defined bythe presence or absence of entries within a mandatory Access ControlList within the home base station registration request, such that if thehome base station is a closed access home base station then the homeaccess base station includes the entries within the Access Control Listin the home base station registration request and if the home basestation is an open access home base station then the home access basestation does not include entries within the Access Control List in thehome base station registration request.

In a further embodiment, the mandatory element may define if the homebase station is an open access home base station, a closed access homebase station or a hybrid access home base station.

The present invention also provides corresponding gateway devices andhome base stations. The invention also provides a message comprisingdata identifying whether or not the home base station is an open accessmode or a closed access mode home base station.

The invention provides, for all methods disclosed, correspondingcomputer programs or computer program products for execution oncorresponding equipment, the equipment itself (user equipment, nodes orcomponents thereof) and methods of updating the equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described, by way of example,with reference to the accompanying drawings in which:

FIG. 1 schematically illustrates a mobile telecommunication system of atype to which the embodiment is applicable;

FIG. 2 is a block diagram of a mobile telephone forming part of thesystem shown in FIG. 1;

FIG. 3 is a block diagram of a home base station forming part of thesystem shown in FIG. 1;

FIG. 4 is a block diagram of a home base station gateway forming part ofthe system shown in FIG. 1;

FIG. 5 is a timing diagram illustrating a registration procedure forregistering the home base station with the home base station gateway;and

FIG. 6 is a timing diagram illustrating a registration procedureperformed when a mobile telephone registers with the home base stationgateway.

BEST MODE FOR CARRYING OUT THE INVENTION

Overview

FIG. 1 schematically illustrates a mobile (cellular) telecommunicationsystem 1 in which a user of a mobile telephone (MT) 3 can communicatewith other users (not shown) via a 3G Radio Access Network (RAN) basestation 5, a Radio Network Controller 7 and a core telephone network 8when the user is away from home 9; and which can communicate with otherusers (not shown) via a home base station (HNB) 11, the Internet 13, ahome base station gateway (HNB-GW) 15 and the core telephone network 8when the user is at home 9. The HNB 11 will typically connect to theHNB-GW 15 via a suitable residential Internet connection such as an ADSLor cable connection.

Mobile Telephone

FIG. 2 schematically illustrates the main components of the mobiletelephone 3 shown in FIG. 1. As shown, the mobile telephone 3 includes atransceiver circuit 23 which is operable to transmit signals to and toreceive signals from the RAN base station 5 or the HNB 11 via one ormore antennae 25. As shown, the mobile telephone 3 also includes acontroller 27 which controls the operation of the mobile telephone 3 andwhich is connected to the transceiver circuit 23 and to a loudspeaker29, a microphone 31, a display 33, and a keypad 35. The controller 27operates in accordance with software instructions stored within memory37. As shown, these software instructions include, among other things,an operating system 39 and a mobile telephone registration module 41. Inthis embodiment, the mobile telephone registration module 41 allows theuser to select the home base station 11 with which the mobile telephone3 will register when the user is at home or when they are within rangeof their HNB 11. The selection may be automatic or manually controlledby the user.

Home Base Station

FIG. 3 is a block diagram illustrating the main components of the homebase station (HNB) 11 shown in FIG. 1. As shown, the HNB 11 includes atransceiver circuit 51 which is operable to transmit signals to, and toreceive signals from, the mobile telephone 3 via one or more antennae 53and which is operable to transmit signals to and to receive signals fromthe HNB-GW 15 via a HNB-GW interface 55. The operation of thetransceiver circuit 51 is controlled by a controller 57 in accordancewith software stored in memory 59. The software stored in memory 59includes, among other things, an operating system 61, a base stationregistration module 63 and a telephone registration module 65. The basestation registration module 63 is operable to register the HNB with theHNB-GW 15 and the mobile telephone registration module 65 is operable toregister the mobile telephone 3 with itself and with the HNB-GW 15.

HNB Gateway

FIG. 4 is a block diagram illustrating the main components of the HNBgateway (HNB-GW) 15 shown in FIG. 1. As shown, the HNB-GW 15 includes atransceiver circuit 101 which is operable to transmit signals to, and toreceive signals from, the HNB 11 via the HNB interface 103 and which isoperable to transmit signals to and to receive signals from the corenetwork 8 via a core network interface 105. The operation of thetransceiver circuit 101 is controlled by a controller 107 in accordancewith software stored in memory 109. The software stored in memory 109includes, among other things, an operating system 111, an HNBregistration module 113 and a mobile telephone registration module 115.The HNB registration module 113 is operable to control the registrationof the HNB 11 and the mobile telephone registration module is operableto control the register the mobile telephone 3 and to perform accesscontrol as required.

In the above description, the mobile telephone 3, the base station 5 andthe HNB gateway 15 are described for ease of understanding as having anumber of discrete modules (such as the registration modules). Whilstthese modules may be provided in this way for certain applications, forexample where an existing system has been modified to implement theinvention, in other applications, for example in systems designed withthe inventive features in mind from the outset, these modules may bebuilt into the overall operating system or code and so these modules maynot be discernible as discrete entities.

Access Control

As mentioned above, three different types of mode of access are definedfor the HNB 11:

-   -   Open access mode: HNB operates as a normal cell via which any        mobile telephone 3 can make and receive calls;    -   Closed access mode: HNB operates as a Closed Subscriber Group        (CSG) cell in which only CSG members are allowed access (this is        the mode as defined in Rel-8); and    -   Hybrid access mode: a CSG cell where at the same time, non-CSG        members are allowed access.

Although the Hybrid access mode is designed for release-9, operatorswould like to recommend that hybrid access mode is implemented inrelease 8 if it does not affect the Release-8 timescale.

As will be appreciated, for HNBs 11 operating in the closed access mode,the HNB-GW 15 must perform access control to restrict access to the corenetwork 8 to only those mobile telephones 3 belonging to the respectivesubscriber groups; whereas for HNBs 11 operating in the open mode, thereis no need for the HNB-GW 15 to perform access control; and for HNBs 11operating in the hybrid mode, there may be no need for the HNB-GW 15 toperform access control. Therefore, in this embodiment, the HNB 11informs the HNB-GW 15 about its access mode capability, so that theHNB-GW 15 can determine whether or not to perform access control for amobile telephone 3 seeking to register through that HNB 11.

A number of techniques will now be described for the HNB 11 to signalits access mode capability to the HNB-GW 15.

HNB Registration Procedure

The purpose of the HNB Registration Procedure is to register the HNB 11with the HNB-GW 15 to enable the HNB-GW to provide service and corenetwork connectivity for the HNB 11. The general process is illustratedin FIG. 5. As shown, the process involves the HNB 11 sending the HNB-GWan HNB REGISTER REQUEST message and the HNB-GW 15 sending an HNBREGISTER ACCEPT message in response. There are a number of differentoptions for signalling the access mode capability of the HNB 11 to theHNB-GW 15.

Option 1: The HNB-GW 15 can infer the access mode of the HNB 11 based onthe Access Control List Information Element (IE). Therefore, it isproposed to include an optional Access Control List IE in the HNBAP HNBREGISTER REQUEST message sent from the HNB 11 to the HNB-GW 15. If theHNB 11 is closed access mode then it will include the optional AccessControl List IE in the HNBAP REGISTER REQUEST message; otherwise if theHNB is open or hybrid access mode, then it will not include the optionalAccess Control list IE in the HNBAP HNB REGISTER REQUEST message.Therefore, a new Access Control List IE needs to be included in theHNBAP HNB REGISTER REQUEST message.

HNB REGISTER REQUEST IE Type and Semantics Assigned PARAMETER PRESENCERANGE Reference Description Criticality Criticality Message Type M 9.2.1yes Reject HNB Identity M 9.2.2 Yes Reject HNB Location M 9.2.3 YesReject Information Access Control List O 9.2.x If this IE is Yes Ignoreincluded, then the access mode of the HNB is considered as “Closed”,else “Open”. (Note 1) PLMN-ID M 9.2.14 yes Reject Cell-ID M 9.2.25 YesReject LAC M 9.2.11 Yes Reject RAC M 9.2.12 Yes Reject SAC M 9.2.13 YesReject

This message is sent by the HNB 11 to the HNB-GW 15 to register the HNB11 at the HNB-GW 15.

Direction: HNB→HNB-GW

9.2.x Access Control List

IE/Group IE type and Semantics Name Presence Range reference descriptionAccess Control 0 . . . maxUEs If this list List is empty, then the ACLis considered as empty. > IMSI M IMSI 9.2.10Note 1: The above option assumes that the HNB-GW 15 treats open accessHNBs and hybrid access HNBs the same and that therefore, hybrid HNBs donot need to inform the HNB-GW 15 about their Access Control List. It iscurrently not clear in the standards whether or not this assumption isvalid. Consequently, if the HNB-GW 15 does needs to have the AccessControl List of the hybrid HNB, then this option will not work.Note 2: It is not clear in the current standards documentation if it ispossible to have a closed mode HNB with no IMSI (International MobileSubscriber Identity) in the Access Control List (ie an empty AccessControl List). If it is assumed that a closed HNB cannot have an emptyAccess Control List, then the presence of the Access Control List IEshould be made mandatory (rather than optional as suggested above) inthe HNBAP HNB REGISTER REQUEST message. In this way, if the HNB-GW 15receives an empty Access Control List IE in the HNBAP HNB REGISTERREQUEST, then the HNB-GW 15 can infer that the HNB 11 is an open accessmode; otherwise, if at least one entry is present in the Access ControlList IE, then the HNB-GW can determine that the HNB 11 is a closed modeHNB.

Option 2: The HNB 11 can indicate its capability (Open, Closed orHybrid) to the HNB-GW 15 during the HNB Registration procedure in theHNBAP HNB REGISTER REQUEST message by using a new HNB CapabilityInformation IE, as shown in the table below.

HNB REGISTER REQUEST IE Type and Semantics Assigned PARAMETER PRESENCERANGE Reference Description Criticality Criticality Message Type M 9.2.1Yes Reject HNB Identity M 9.2.2 Yes Reject HNB Location M 9.2.3 YesReject Information HNB Capability M 9.2.y Yes Reject Information PLMN-IDM 9.2.14 Yes Reject Cell-ID M 9.2.25 Yes Reject LAC M 9.2.11 Yes RejectRAC M 9.2.12 Yes Reject SAC M 9.2.13 Yes Reject9.2.y HNB Capability Information

HNB Capability Information IE is sent from the HNB to HNB-GW to provideinformation on the capability of the HNB.

IE/GROUP IE Type and Semantics NAME PRESENCE RANGE Reference DescriptionHNB Capability Information > Access M (Open, Closed, control typeHybrid)

Option 3: The OAM (Operations and Maintenance) functionality for theHNB-GW 15 stores the HNB access mode for each HNB 11. Upon successfulHNB Registration at the HNB-GW 15, the HNB-GW 15 retrieves the HNBaccess mode from the OAM database (not shown) and performs the accesscontrol accordingly.

UE Registration Procedure

Based on the possible options described above, the HNB-GW 15 will knowthe HNB access control mode during the HNB Registration procedure. TheHNB-GW 15 will store this information for further use, until either theHNB 11 deregisters itself or updates this information via another HNBAPprocedure. In one embodiment, the mobile telephone registration(illustrated in FIG. 6) shall be performed using the following steps:

-   -   1. Upon camping on the HNB 11, the mobile telephone (MT) 3        initiates an initial NAS procedure (e.g. LU Procedure) by        establishing an RRC connection with the HNB 11.    -   2. The MT 3 then transmits an RRC Initial Direct Transfer        message carrying the initial NAS message (e.g. Location Updating        Request message) with NAS level identity (IMSI or TMSI, P-TMSI        etc. . . . ).    -   3. The HNB 11 initiates MT 3 registration towards the HNB-GW 15.        If HNB 11 is closed or hybrid access mode then before starting        the mobile telephone Registration procedure, the HNB performs        the NAS COMMON ID procedure in order to get the IMSI for the        mobile telephone 3, if such identity is not received in the RRC        Connection Establishment or Initial Direct Transfer message.    -   4. HNB 11 may optionally perform access control based on IMSI        and access control list.    -   5. The 3G HNB 11 attempts to register the mobile telephone 3 on        the HNB-GW 15 by transmitting the HNBAP UE REGISTER REQUEST,        containing the mobile telephone identity (IMSI in case of a        closed/hybrid access HNB, or TMSI/IMSI in case of an open access        HNB).    -   6. If the HNB 11 is open access mode then the HNB-GW 15 shall        accept the mobile telephone 3 registration and allocate a        context-id for the mobile telephone 3.    -   7. If the HNB 11 is closed access mode then the HNB-GW 15 shall        perform access control for the particular mobile telephone 3        attempting to utilize the specific 3G HNB.    -   8. If the HNB 11 is hybrid access mode then the HNB-GW 15 shall        perform access control for the particular mobile telephone 3        attempting to utilize the specific 3G HNB. If the access control        succeeds, then the HNB-GW 15 accepts the registration of the        mobile telephone 3 and allocates a context-id for the mobile        telephone 3. In this case, the mobile telephone 3 is considered        as a CSG mobile telephone. This information is stored and could        be used for purposes such as service differentiation etc. On the        other hand, if the access control fails, then the HNB-GW 15        still accepts the registration of the mobile telephone 3 and        allocates a context-id for the mobile telephone 3. However, in        this case the mobile telephone 3 is considered as a non-CSG        mobile telephone (which information is stored and could be used        for purposes such as service differentiation etc).    -   9. If the HNB-GW accepts the mobile telephone registration        request then the HNB-GW shall send the UE REGISTRATION ACCEPT        message to the HNB including the unique context id.    -   10. Upon successful completion of the mobile telephone        Registration Request message, the HNB 11 sends a CONNECT message        containing the RANAP Initial UE message.    -   11. Upon the reception of the RUA CONNECT message, the HNB-GW 15        performs the SCCP Connection establishment towards the core        network 8. HNB-GW 15 may include the Initial UE Message in the        SCCP CR message. Alternatively, the HNB-GW 15 sends the Initial        UE Message upon successful establishment of SCCP connection        establishment.

Modifications and Alternatives

A detailed embodiment has been described above. As those skilled in theart will appreciate, a number of modifications and alternatives can bemade to the above embodiment whilst still benefiting from the inventionsembodied therein.

In the above embodiment, a mobile telephone based telecommunicationssystem was described. As those skilled in the art will appreciate, thesignalling techniques described in the present application can beemployed in other communications system. Other communications nodes ordevices may include user devices such as, for example, personal digitalassistants, laptop computers, web browsers, etc.

In the above embodiments, a number of software modules were described.As those skilled will appreciate, the software modules may be providedin compiled or un-compiled form and may be supplied to the base stationor to the mobile telephone as a signal over a computer network, or on arecording medium. Further, the functionality performed by part or all ofthis software may be performed using one or more dedicated hardwarecircuits. However, the use of software modules is preferred as itfacilitates the updating of base station 5 and the mobile telephones 3in order to update their functionalities.

Various other modifications will be apparent to those skilled in the artand will not be described in further detail here.

The following is a detailed description of the way in which the presentinventions may be implemented in the currently proposed 3GPP standard.Whilst various features are described as being essential or necessary,this may only be the case for the proposed 3GPP standard, for exampledue to other requirements imposed by the standard. These statementsshould not, therefore, be construed as limiting the present invention inany way.

1 INTRODUCTION

During the recent RAN#3 meetings, the HNB registration procedure hasbeen agreed and captured in the Stage-2 document. The list of IEs sentfrom the HNB to HNB-GW in the HNB REGISTER REQUEST message is currentlydiscussed and some IEs [2] have been already agreed. This contributiondiscusses the HNB capability information to be included in the HNBREGISTER REQUEST message.

It is assumed that pre-release-8 UEs will remain exist in the actualfield for quite long time. Therefore, the network has to supportpre-release-8 and CSG UEs simultaneously. Also, It is already agreedthat access control mechanism is mandatory at the HNB-GW whereasoptional at the HNB for pre-release-8 UEs. Moreover, with the evolvingscenarios of HNB deployments, it is realized the HNB could be operatedwith different access control mechanisms, namely “Open”, “Closed” and“Hybrid”. Such agreement is already made in SA1 [1]. As clear, if theHNB is open or hybrid access, then mandatory access control at HNB-GW isnot required for pre-release-8 UEs. Therefore, for efficient workingalready it is necessary that the HNB access mode capability should beknown to the HNB-GW.

2 DISCUSSION

4.1. 2.1 Background

As mentioned in [1], three different types of mode of access are definedfor HNB/HeNB.

-   -   Open access mode: HNB/HeNB operates as a normal cell, i.e.        non-CSG cell.    -   Closed access mode: HNB/HeNB operates as a CSG cell. This is the        mode as defined in Rel-8. This is a CSG cell where only CSG        members are allowed access.    -   Hybrid access mode: a CSG cell where at the same time, non-CSG        members are allowed access.

Although the LS reply [1] refers to release-9, it is specificallymentioned that the operators would like to recommend that hybrid accessmode is implemented in release 8 if it does not affect the Release-8timescale.

In order avoid unnecessary access control at HNB-GW when the HNB is openaccess or hybrid access, the HNB-GW must know the access mode capabilityof the HNB.

This paper discusses some of the possible solutions in the followingsections.

2.2 HNB Registration Procedure

The purpose of the HNB Registration Procedure is to register the HNBwith the HNB-GW to enable the HNB-GW to provide service and core networkconnectivity for the HNB.

Option 1: The HNB-GW can infer the access mode of the HNB based on theAccess Control List IE received from the HNB. Therefore, it is proposedto include the optional Access Control List IE in the HNBAP HNB REGISTERREQUEST message. If the HNB is closed access mode then it will includethe optional Access Control List IE in the HNBAP REGISTER REQUESTmessage; otherwise if the HNB is open access mode, then it will notinclude the optional Access Control list IE in the HNBAP HNB REGISTERREQUEST message. Therefore, new Access Control List IE needs to beincluded in the HNBAP HNB REGISTER REQUEST message.

4.2. HNB Register Quest

This message is sent by the HNB to the HNB-GW to register the HNB at theHNB-GW.

Direction: HNB → HNB-GW IE Type and Semantics Assigned PARAMETERPRESENCE RANGE Reference Description Criticality Criticality MessageType M 9.2.1 yes Reject HNB Identity M 9.2.2 Yes Reject HNB Location M9.2.3 Yes Reject Information Access Control O 9.2.x If this IE is YesIgnore List included, then the access mode of the HNB is considered as“Closed”, else “Open”. (Note 1) PLMN-ID M 9.2.14 yes reject Cell-ID M9.2.25 Yes reject LAC M 9.2.11 Yes Reject RAC M 9.2.12 Yes reject SAC M9.2.13 Yes Reject Note 1: It is assumed that, HNB-GW will need samehandling for “Open” and “Hybrid” access mode of operation.9.2.x Access Control List

IE/ IE type Group and Semantics Name Presence Range referencedescription Access 0 . . . maxUEs If this list is empty, Control thenthe ACL is List considered as empty. >IMSI M IMSI 9.2.10 Note 1: Theabove option assumes that from HNB-GW point of view, open access HNB andhybrid access HNB is the same. Therefore, it is not necessary to informabout the ACL for the hybrid mode HNB to the HNB-GW. It is currently notclear in the standards whether the HNB-GW needs to have the ACL forhybrid HNB. If the HNB-GW needs to have the ACL of the hybrid HNB, thenthis option will not work. Note 2: It is not clear in the specificationif it is possible to have closed mode HNB with no IMSI in the ACL. If itis assumed that a closed HNB cannot have an empty ACL, then the AccessControl List IE should be mandatory present in the HNBAP HNB REGISTERREQUEST message. Then, if the HNB-GW receives empty Access Control ListIE in the HNBAP HNB REGISTER REQUEST, then the HNB is considered as openaccess mode; otherwise, if at least one entry is present in the AccessControl List IE, then the HNB is considered as closed mode HNB.Option 2: The HNB can indicate its capability during the HNBRegistration procedure in the HNBAP HNB REGISTER REQUEST message byusing a new HNB Capability Information IE.

IE Type and Semantics Assigned PARAMETER PRESENCE RANGE ReferenceDescription Criticality Criticality Message Type M 9.2.1 yes Reject HNBIdentity M 9.2.2 Yes Reject HNB Location M 9.2.3 Yes Reject InformationHNB Capability M 9.2.x Yes Reject Information PLMN-ID M 9.2.14 yesReject Cell-ID M 9.2.25 Yes Reject LAC M 9.2.11 Yes Reject RAC M 9.2.12Yes Reject SAC M 9.2.13 Yes Reject4.3. 9.2.y Capability Information

HNB Capability Information IE is sent from the HNB to HNB-GW to provideinformation on the capability of the HNB.

IE Type IE/GROUP and Semantics NAME PRESENCE RANGE Reference DescriptionHNB Capability Information > Access M (Open, control type Closed,Hybrid)Option 3: The OAM for HNB-GW stores the HNB access mode for each HNB.Upon successful HNB Registration at the HNB-GW, the HNB-GW retrieves theHNB access mode from OAM database and performs the access controlaccordingly.2.2 UE Registration Procedure:

Based on the possible solutions mentioned in section 2.1, the HNB-GWwill know the HNB access control mode during the HNB Registrationprocedure. The HNB-GW will store this information for further use, untileither the HNB deregisters itself or updates this information viaanother HNBAP procedure. In FIG. 6, UE is used instead of the mobiletelephone (TE) 3. The UE registration shall be performed using thefollowing steps;

-   -   12. Upon camping on the HNB, the UE initiates an initial NAS        procedure (e.g. LU Procedure) by establishing an RRC connection        with the HNB.    -   13. The UE then transmits a RRC Initial Direct Transfer message        carrying the initial NAS message (e.g. Location Updating Request        message) with NAS level identity (IMSI or TMSI, P-TMSI etc. . .        . ).    -   14. The HNB initiates UE registration towards HNB-GW. If HNB is        closed/hybrid access mode then before starting the UE        Registration procedure, HNB performs NAS COMMON ID procedure in        order to get the UE IMSI, if such identity is not received in        the RRC Connection Establishment or Initial Direct Transfer        message.    -   15. HNB may optionally perform access control based on IMSI and        access control list.    -   16. The 3G HNB attempts to register the UE on the HNB-GW by        transmitting the HNBAP UE REGISTER REQUEST, containing the UE        identity (IMSI in case of closed/hybrid access HNB, or TMSI/IMSI        in case of open access mode).    -   17. If the HNB is open access then the HNB-GW shall accept the        UE registration and allocate a context-id for the UE.    -   18. If the HNB is closed access mode then the HNB-GW shall        perform access control for the particular UE attempting to        utilize the specific 3G HNB.    -   19. If the HNB is hybrid access mode then the HNB-GW shall        perform access control for the particular UE attempting to        utilize the specific 3G HNB. If the access control succeeds,        HNB-GW accepts the UE registration and allocates a context-id        for the UE. The UE is considered as CSG UE, which could be used        for purposes such as service differentiations etc. If the access        control fails, still the HNB-GW accepts the UE registration and        allocates a context-id for the UE. However, this UE is        considered as non-CSG UEs which could be used for purposes such        as service differentiations etc.    -   20. If the HNB-GW accepts UE registration request then the        HNB-GW shall send the UE REGISTRATION ACCEPT message to the HNB        including the unique context id.    -   21. Upon successful completion of the UE Registration Request        message, the HNB sends a CONNECT message containing the RANAP        Initial UE message.    -   22. Upon the reception of the RUA CONNECT message, the HNB-GW        performs the SCCP Connection establishment towards the CN.        HNB-GW may include the Initial UE Message in the SCCP CR        message. Alternatively, the HNB-GW sends the Initial UE Message        upon successful establishment of SCCP connection establishment.

3 CONCLUSION

Introduce the new HNB Capability Information IE in the HNBAP HNBREGISTER REQUEST message.

This application is based upon and claims the benefit or priority fromUnited Kingdom Patent Application No. 0820182.4, filed on Nov. 4, 2008,the disclosure of which is incorporated herein in its entirety byreference.

The invention claimed is:
 1. A base station which communicates with abase station gateway, the base station comprising: a transmissioncircuit configured to transmit a base station register request to thebase station gateway, wherein the base station register request includesat least information identifying whether the base station is an openmode base station or a closed mode base station, wherein the informationidentifying whether the base station is an open mode base station or aclosed mode base station is based on data stored in a memory; and areceiving circuit configured to receive a base station register acceptmessage from the base station gateway.
 2. A method comprising:transmitting, from a base station to a base station gateway, a basestation register request, wherein the base station register requestincludes at least information identifying whether the base station is anopen mode base station or a closed mode base station, wherein theinformation identifying whether the base station is an open mode basestation or a closed mode base station is based on data stored in amemory; and receiving, by the base station, from the base stationgateway, a base station register accept message.
 3. The base stationaccording to claim 1, wherein the data stored in the memory comprisesthe information identifying whether the base station is an open modebase station or a closed mode base station.
 4. The base stationaccording to claim 2, wherein the data stored in the memory comprisesthe information identifying whether the base station is an open modebase station or a closed mode base station.